The present invention relates to a recyclable article a n d a sheet-like member included in the article.
A great number of articles each having a first and a second part adhered together by an adhesive are used in, e.g., copiers, facsimile apparatuses, printers, word processors, personal computers and other office equipments, television sets, video tape recorders and other equipments for public use, buildings, railroads, ships, and toys.
A copier, for example, is made up of various kinds of articles including a casing, a front door and image forming devices arranged within the casing. These articles each have a first part and a second part. The front door, for example, has a door body and a sheet-like member adhered to the door body and usually called a decal. The door body and decal are the first part and second part, respectively. The decal is a sheet-like piece implemented as, e.g., a resin sheet, resin film or thin flexible or rigid resin plate. Necessary information are printed on the decal or can be entered later. The decal is adhered to, e.g., the surface of the casing or that of a toner cartridge and is extensively used with equipments other than copiers as well. The casing of the copier has a casing body and a sound-absorbing sheet-like member adhered to the casing body and formed of a foam material. In this case, the casing body and sound-absorbing member are the first part and second part, respectively. An article made up of a first and a second part sometimes constitutes a single product alone.
Today, there is an increasing demand for recyclable products in order to further promote the protection of environment and the saving of limited resources. To meet this demand, it is necessary to recycle and reuse as far as possible the parts of a disused product, e.g., electronic equipment or automotive vehicle. In this respect, the article consisting of a first and a second part, as stated earlier, should preferably be formed of a thermoplastic resin. When such an article is disused, it can be, e.g., shredded into pellets, melted by heat, and then molded to produce another article.
The problem with the above recycling scheme is as follows. Assume that the first and second parts constituting the article are formed of different materials. Then, when the article is bodily shredded and melted, the materials of the two parts do not dissolve in each other and are apt to deteriorate the mechanical strength and other characteristics of an expected molding. For example, should the door body or first part and the decal or second part of the front door of the copier be formed of materials far different in property from each other, a molding produced by shredding and melting the two parts would have characteristics deteriorated too much to implement a new door body.
In light of the above, an article whose first and second parts are formed of thermoplastic resins soluble in each gather is proposed in Japanese Patent Laid-Open Publication No. 8-34088. This kind of article can be shredded, melted and then molded with the first and second parts adhered together, preventing the characteristics of an expected molding from being deteriorated. In addition, recycling the article without separating the first and second parts reduces the cost.
However, our extended researches on the recyclability of various kinds of products showed that the approach taught in the above document cannot promote smooth recycling alone, as follows.
Recycling a certain article refers not only to shredding and melting the article for producing a new molding, but also to reusing, if the article is free from noticeable damage or contamination, the article without shredding or melting it. Again, consider the front door of the copier. If the door body of the front door is still usable when the copier is disused and collected, then it is reused as a front door. Specifically, the decal of the front door is peeled off the door body because it is usually discolored or otherwise damaged due to, e.g., aging. Then, the door body is cleaned and, if necessary, reconditioned. Subsequently, a new decal is adhered to the clean door body in order to reuse the front cover. That is, the second part is separated from the first part, and then a new second part is fitted on the first part by an adhesive.
Let using a certain article again without shredding or melting it be referred to as "reusing", as distinguished from "recycling" involving shredding and melting. When a certain article is collected, it is preferable to determine whether the article should be reused or recycled, depending on its degree of contamination and damage as well as its history of use. This is because reusing an article without shredding or melting is practicable with less energy and cost, yet with a higher efficiency, than recycling. If the article is critically damaged or repeatedly used in the past, it is shredded and melted in order to produce a new molding.
To recycle the disused article, the first and second parts constituting it are formed of thermoplastic resins soluble in each other in order to provide a new molding with desirable characteristics, as stated earlier. However, the problem is that when the second part is removed from the first part, the adhesive is apt to remain on the first part in a great amount. Specifically, because the adhesive between the first and second parts soluble in each other exerts substantially the same adhesion force on the two parts, the adhesive either partly or almost entirely remains on the first part at the time of removal of the second part.
Assume that the first part on which the adhesive is left is simply cleaned, and then a new second part is fitted on the first part by an adhesive. Then, it is likely that the adhesive left on the first part reduces the adhesion force to act on the new second part and degrades the appearance of the resulting article. For example, assume that the decal or second part is peeled off the door body or first part while leaving a great amount of adhesive on the door body, and then a new decal is adhered to the door body. Then, the adhesive remaining on the door body lowers the adhesion force to act on the new decal, and in addition causes the surface of the new decal to rise and thereby deteriorates the appearance to a critical degree. Even when the first part from which the second part has been removed is reused without any new second part, the adhesive remaining on the first part degrades the appearance of the article.
Therefore, the adhesive left on the first part at the time of separation of the second part must be removed by, e.g., hand. However, the adhesive exerting a great adhesion force even on the first part, as stated previously, cannot be easily removed from the first part. This results in time- and labor-consuming work and increases the overall recycling cost.